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1967 PL411 HeadLight and Relay Problem


Chiquidrac

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Hi Guys,

I had a problem with the light system on my PL411, no low lights, no back lights, and when I switch to hi beams the four lights will come on but the front parking lights will go off. 

 

So I did a lot of research on this forums and found enough information to troubleshoot and figured out where the problem was, the first thing I did was to  it turned out that my back lights blew off and seems to me like the low beans are burned out too.  

 

DSC04533_zpsoewd24dc.jpg

 

So the first thing I did, following some of the advise on this forums, was to make sure the light switch worked, I also checked continuity on the fuses, and traced the cables following the wiring diagrams available here too.  There were some problems with the connections (mainly rust) on the fuse block and decided to clean it and just in case replaced all the fuses (something I think needs to be done in all cars this old)

 

DSC04534_zpsicyli2oo.jpg

 

After I checked for correct functioning of switches, continuity, and voltages I ended up isolating the problem to the light relay

 

DSC04537_zpswwkh79sc.jpg

 

What was happening was that the relay will get voltage in all the terminals that are outlined in the circuit diagram, but voltage was not flowing to the low beam terminal once the light switch was turned to the second position, but if I set the high beams on the turn signal lever then all 4 lights will come on and the front marker lights will turn off.

After more research and playing with different options, I figured out that the gap in the relay contacts is important and that was causing the lack of current flowing to the low beams (the relay will make a click and move the 2 legs to a different positions when actuating the high beams) but because of the ap in between them the relay wasn't performance the way it was supposed to do (at least that was my own conclusion but I am not an expert)

 

DSC04544_zpsnqkkcnox.jpg

 

After playing with carefully bending the legs and adjusting the gap I was able to get current flowing the way is supposed to do.

 

Now, after I got this done I was thinking about the reason for the blown bulbs and my conclusion is that there is a problem with the voltage/current flowing in the circuits, so I measured the voltage with in 2 different points with the engine off

 

DSC04539_zpsogfeiuzd.jpg

 

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and did the same with the engine running

 

DSC04542_zpszhy1pzsl.jpg

 

DSC04541_zpsoftcf5ak.jpg

 

Very different results!  So I am assuming I have a bad voltage regulator

 

DSC04535_zpsciff4jrj.jpg

 

but that is my conclusion and here is where I need your help, I think the relay and everything else is working now but I really like to know if you guys have some suggestions and ideas.  

 

I just want to thank you all for the information in the forums because even I am not an expert I was able to find all the information I needed to get most of it solved, the search function is really your best friend!

 

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Sure sounds like a flakey 12 volt battery/alternator Voltage Regulator problem to me.  You "can" adjust the mechanical VR but skip over the agony of repetitive tweaks and get an electronic VR that fits the mechanical mounting holes and is a direct plug in for the electrical connection.  If you cannot find a real part number, say so and I will look up the Standard [that's the manufacturer] part number.

 

The complexity of two headlight relays traces to standard JN practices.  Gas and car batteries are expensive so when driving in the city, no high beams at night.  You drive on low beams and when you come to a stop light, you down switch to the parking lamps until the light changes.  Set the 411 lighting switch to Park, then when you hit what would normally be High beam position, your Low beams come on.  Return to normal and you are on parking lamps.  BTW, standard JN practice is also to switch the engine off and restart when the long duration red light changes.

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Ok thanks for the info, I just found one extra regulator in my spare parts, installed and it works now!  Also, I called Autozone and order a new regulator that will be coming tomorrow.

So at the end there were 3 problems that combined to get me stuck for a while,

 

1.- Bad voltage regulator

2.- Blown bulbs and headlamp

3.- gap between the light relay legs

 

It works now and the best part is that I learned more about the datsun electrical system.

 

Thank you again.

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